Class MpUnboundedXaddArrayQueue<R extends MpUnboundedXaddChunk<R,​E>,​E>

    • Constructor Detail

      • MpUnboundedXaddArrayQueue

        MpUnboundedXaddArrayQueue​(int chunkSize,
                                  int maxPooledChunks)
        Parameters:
        chunkSize - The buffer size to be used in each chunk of this queue
        maxPooledChunks - The maximum number of reused chunks kept around to avoid allocation, chunks are pre-allocated
    • Method Detail

      • chunkSize

        public final int chunkSize()
      • maxPooledChunks

        public final int maxPooledChunks()
      • newChunk

        abstract R newChunk​(long index,
                            R prev,
                            int chunkSize,
                            boolean pooled)
      • currentProducerIndex

        public long currentProducerIndex()
        Description copied from interface: QueueProgressIndicators
        This method has no concurrent visibility semantics. The value returned may be negative. Under normal circumstances 2 consecutive calls to this method can offer an idea of progress made by producer threads by subtracting the 2 results though in extreme cases (if producers have progressed by more than 2^64) this may also fail.
        This value will normally indicate number of elements passed into the queue, but may under some circumstances be a derivative of that figure. This method should not be used to derive size or emptiness.
        Specified by:
        currentProducerIndex in interface QueueProgressIndicators
        Returns:
        the current value of the producer progress index
      • currentConsumerIndex

        public long currentConsumerIndex()
        Description copied from interface: QueueProgressIndicators
        This method has no concurrent visibility semantics. The value returned may be negative. Under normal circumstances 2 consecutive calls to this method can offer an idea of progress made by consumer threads by subtracting the 2 results though in extreme cases (if consumers have progressed by more than 2^64) this may also fail.
        This value will normally indicate number of elements taken out of the queue, but may under some circumstances be a derivative of that figure. This method should not be used to derive size or emptiness.
        Specified by:
        currentConsumerIndex in interface QueueProgressIndicators
        Returns:
        the current value of the consumer progress index
      • producerChunkForIndex

        final R producerChunkForIndex​(R initialChunk,
                                      long requiredChunkIndex)
        We're here because currentChunk.index doesn't match the expectedChunkIndex. To resolve we must now chase the linked chunks to the appropriate chunk. More than one producer may end up racing to add or discover new chunks.
        Parameters:
        initialChunk - the starting point chunk, which does not match the required chunk index
        requiredChunkIndex - the chunk index we need
        Returns:
        the chunk matching the required index
      • appendNextChunks

        protected final R appendNextChunks​(R currentChunk,
                                           long currentChunkIndex,
                                           long chunksToAppend)
      • newOrPooledChunk

        private R newOrPooledChunk​(R prevChunk,
                                   long nextChunkIndex)
      • moveToNextConsumerChunk

        final void moveToNextConsumerChunk​(R cChunk,
                                           R next)
        Does not null out the first element of `next`, callers must do that
      • iterator

        public java.util.Iterator<E> iterator()
        Specified by:
        iterator in interface java.util.Collection<R extends MpUnboundedXaddChunk<R,​E>>
        Specified by:
        iterator in interface java.lang.Iterable<R extends MpUnboundedXaddChunk<R,​E>>
        Specified by:
        iterator in class java.util.AbstractCollection<E>
      • size

        public int size()
        Description copied from interface: MessagePassingQueue
        This method's accuracy is subject to concurrent modifications happening as the size is estimated and as such is a best effort rather than absolute value. For some implementations this method may be O(n) rather than O(1).
        Specified by:
        size in interface java.util.Collection<R extends MpUnboundedXaddChunk<R,​E>>
        Specified by:
        size in interface MessagePassingQueue<R extends MpUnboundedXaddChunk<R,​E>>
        Specified by:
        size in class java.util.AbstractCollection<E>
        Returns:
        number of messages in the queue, between 0 and Integer.MAX_VALUE but less or equals to capacity (if bounded).
      • isEmpty

        public boolean isEmpty()
        Description copied from interface: MessagePassingQueue
        This method's accuracy is subject to concurrent modifications happening as the observation is carried out.
        Specified by:
        isEmpty in interface java.util.Collection<R extends MpUnboundedXaddChunk<R,​E>>
        Specified by:
        isEmpty in interface MessagePassingQueue<R extends MpUnboundedXaddChunk<R,​E>>
        Overrides:
        isEmpty in class java.util.AbstractCollection<E>
        Returns:
        true if empty, false otherwise
      • relaxedOffer

        public boolean relaxedOffer​(E e)
        Description copied from interface: MessagePassingQueue
        Called from a producer thread subject to the restrictions appropriate to the implementation. As opposed to Queue.offer(Object) this method may return false without the queue being full.
        Specified by:
        relaxedOffer in interface MessagePassingQueue<R extends MpUnboundedXaddChunk<R,​E>>
        Parameters:
        e - not null, will throw NPE if it is
        Returns:
        true if element was inserted into the queue, false if unable to offer
      • drain

        public int drain​(MessagePassingQueue.Consumer<E> c)
        Description copied from interface: MessagePassingQueue
        Remove all available item from the queue and hand to consume. This should be semantically similar to:
         M m;
         while((m = relaxedPoll()) != null){
         c.accept(m);
         }
         
        There's no strong commitment to the queue being empty at the end of a drain. Called from a consumer thread subject to the restrictions appropriate to the implementation.

        WARNING: Explicit assumptions are made with regards to MessagePassingQueue.Consumer.accept(T) make sure you have read and understood these before using this method.

        Specified by:
        drain in interface MessagePassingQueue<R extends MpUnboundedXaddChunk<R,​E>>
        Returns:
        the number of polled elements
      • fill

        public int fill​(MessagePassingQueue.Supplier<E> s)
        Description copied from interface: MessagePassingQueue
        Stuff the queue with elements from the supplier. Semantically similar to:
         while(relaxedOffer(s.get());
         
        There's no strong commitment to the queue being full at the end of a fill. Called from a producer thread subject to the restrictions appropriate to the implementation.

        Unbounded queues will fill up the queue with a fixed amount rather than fill up to oblivion. WARNING: Explicit assumptions are made with regards to MessagePassingQueue.Supplier.get() make sure you have read and understood these before using this method.

        Specified by:
        fill in interface MessagePassingQueue<R extends MpUnboundedXaddChunk<R,​E>>
        Returns:
        the number of offered elements
      • drain

        public int drain​(MessagePassingQueue.Consumer<E> c,
                         int limit)
        Description copied from interface: MessagePassingQueue
        Remove up to limit elements from the queue and hand to consume. This should be semantically similar to:

        
           M m;
           int i = 0;
           for(;i < limit && (m = relaxedPoll()) != null; i++){
             c.accept(m);
           }
           return i;
         

        There's no strong commitment to the queue being empty at the end of a drain. Called from a consumer thread subject to the restrictions appropriate to the implementation.

        WARNING: Explicit assumptions are made with regards to MessagePassingQueue.Consumer.accept(T) make sure you have read and understood these before using this method.

        Specified by:
        drain in interface MessagePassingQueue<R extends MpUnboundedXaddChunk<R,​E>>
        Returns:
        the number of polled elements
      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.util.AbstractCollection<E>